The Ledger The Ledger
MILEPOST 1221
The ledger, through September 27
Mean absolute temperature error runs 2.22°F at day 1 and 3.87°F at day 7, over 522,450 settled forecast-observation pairs.
Every forecast this network publishes for a station with an ASOS report is compared against that report once the valid time has passed, and the residual is written down. This is the standing table for August 28–September 27, 2026.
| Lead | NDFD | NBM | pairs |
|---|---|---|---|
| Day 1 | 2.28 | 2.22 | 71,381 |
| Day 2 | 2.51 | 2.43 | 71,393 |
| Day 3 | 2.77 | 2.66 | 71,692 |
| Day 4 | 3.01 | 2.89 | 71,992 |
| Day 5 | 3.33 | 3.19 | 71,767 |
| Day 6 | 3.67 | 3.54 | 71,084 |
| Day 7 | 4.06 | 3.87 | 57,465 |
| Day 8 | — | 4.17 | 35,676 |
Mean absolute error, °F, temperature. ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.
The numbers in this piece, with what they are measured against
| day-1 mean absolute temperature error, NBM Forecast Network verification ledger |
2.22 °F | of 35,387 August 28–September 27, 2026 |
| day-3 mean absolute temperature error, NBM Forecast Network verification ledger |
2.66 °F | of 35,696 August 28–September 27, 2026 |
| day-5 mean absolute temperature error, NBM Forecast Network verification ledger |
3.19 °F | of 35,846 August 28–September 27, 2026 |
| day-7 mean absolute temperature error, NBM Forecast Network verification ledger |
3.87 °F | of 35,620 August 28–September 27, 2026 |
| day-1 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.28 °F | of 35,994 August 28–September 27, 2026 |
| day-3 mean absolute temperature error, NDFD Forecast Network verification ledger |
2.77 °F | of 35,996 August 28–September 27, 2026 |
| day-5 mean absolute temperature error, NDFD Forecast Network verification ledger |
3.33 °F | of 35,921 August 28–September 27, 2026 |
| day-7 mean absolute temperature error, NDFD Forecast Network verification ledger |
4.06 °F | of 21,845 August 28–September 27, 2026 |
- Milepost
- 1221 · laid 2026-09-27T00:25:32Z
- Desk
- ledger v1
- Method
- ASOS reports at :53 and the forecast is stamped on the hour, so a forecast is paired with the nearest observation within 30 minutes and otherwise left unscored.
- Source
- /home/maue/forecastpoints/data/verify/2026-08.ndjson
/home/maue/forecastpoints/data/verify/2026-09.ndjson - Digest
- e3b2de9525faf1d2226881e0995b36b49918fb39fc299dceabd8c7e4e81d6bd4
- Machine
- JSON